Mechanical apparatus



Sept. 14, 1965 G. N. WILLIS MECHANICAL APPARATUS Filed March 7, 1963 2 Sheets-Sheet l llb lOd 4 INVENTOR.

6c GRANT NOBLE WILLIS id A TTORNE Y swam Sept. 14, 1965 G. N. WILLIS MECHANICAL APPARATUS 2 Sheets-Sheet 2 Filed March 7, 1963 INVENTOR. GRANT NOBLE WILLIS mm LW United States Patent Ofifice 3266559156 Patented Sept. 14, 11965 3,205,916 MECHANICAL APPARATUS Grant Noble Willis, Bristol, 02m assignor to The American Manufacturing Company, Inc, Brooklyn, N.Y., a corporation of Delaware Filed Mar. 7, 1963, Ser. No. 263,634 15 Claims. (Cl. Mil-93.2)

This invention relates to a strapping device and in particular to a novel tool for tensioning non-metallic strapping about an object and severing the same after a seal has been applied to overlapping portions thereof.

It has been proposed to employ plastic strapping in lieu of steel or other metallic strapping for certain applications. Steel strapping presents problems of storage, Weight, safety to handling personnel, inflexibility, and scrap disposal, among others. It has therefore been proposed to use strapping made from plastic materials. One such material which has been found eminently suitable for this purpose is polypropylene which has been made highly fibrous by molecular orientation due to elongation and has been marketed under the trademark Amcostrap.

In the development of this type of strapping for commercial usage it was found that tools and seals for conventional steel strapping would not work satisfactorily. The highly-oriented nature of the strapping which renders it stronger in the direction of its longitudinal axis than in a direction transverse thereto and the fact that the surface of the polypropylene strapping is somewhat slippery, made it necessary to devise special methods and devices for tensioning and sealing the strap.

Mechanisms for tensioning steel strapping were first tried with the plastic strapping mentioned above, but it was found that their clamping assemblies were so constructed as to engage just a relatively small portion of the free end of the strapping and when the tension was increased, the strapping tore at the clamping contact. It was also found that pawl and rachet means which were conventionally used to engage the other end of the strapping and pull it also invariably tore the plastic strapping. From such studies of the use of conventional steel strapping tools with polypropylene strapping came the finding that the free end thereof had to be clamped and the other end had to be pulled by apparatus which .distributed the pressure at the respective contact points.

It is therefore among the objects of the present invention to provide:

(1) A novel strap-tensioning device for non-metallic strapping.

(2) A novel strap-tensioning and severing device for non-metallic strapping.

(3) A novel strap-tensioning and severing device for plastic strapping which does not deform said strapping.

(4) A novel strap-tensioning device which is designed to clamp one end thereof and to advance the other end thereof without unduly localizing the pressure exerted transverse to the plane of the strapping.

(5) A novel strap-tensioning and cutting device for non-metallic strapping which is designed to sever said strapping after it has been tensioned without producing frayed ends thereof.

(6) A novel strap-tensioning and cutting device for highly-oriented essentially polypropylene strapping which is designed to cut said strapping just after said strapping has been released from the tensioning mechanism of said device.

These and other objects of the invention will occur to those skilled in the art upon perusal of the drawings and specification herein.

These objects are accomplished, in accordance with my invention, by providing a device which includes a tensioning means comprised of three rollers through which the strapping is threaded after it has been clamped at its free end and passed around a package. Two of the rollers are constructed to revolve about a fixed axis whereas the third roller which is intermediate them is designed for movement not only around its axis but also for limited movement along its axis and transverse thereto. This universal roller is so constructed that it avoids localization of undue pressures on the tape which is threaded between the rollers thereby preventing pinching and deformation, tearing or weakening of the tape as it is advanced through the rollers.

The device includes novel means for clamping the free end of the strapping and for cutting another portion thereof after a seal has been used to connect overlapping portions of the strap together in response to a pull on a trigger. The trigger is so coupled to the clamping and cutting means that in a single pull thereof the sealed strapping is released from the clamping means and tension on the strap is somewhat relaxed just prior to the time that the cutting means operates. It has been found that by arranging the unclamping and cutting operations in this sequence, the ends of the tape where the cut is made do not become frayed.

FIGURE 1 is a side elevation, partly in phantom, of my novel device as it would be used to tension strapping about a desired object as shown.

FIGURE 2 is a plan view of my device, partly in phantom.

FIGURE 3 is a fragmentary sectional view of the apparatus shown in FIG. 2 taken along the section line 33 in the direction indicated.

FIGURE 4 is a sectional view of the apparatus shown in FIG. 1 taken along the section line 4-4 in the direction indicated.

FIGURE 5 is an exploded view of the main constituents of the clamping and cutting assembly.

FIGURE 6 is a sectional view of the apparatus shown in FIG. 1 taken along the section line 66.

FIGURES 7 and 8 are two fragmentary sectional schematic views of the clamping apparatus depicting the clamped and unclamped states respectively.

FIGURE 9 is a fragmentary sectional view of the apparatus shown in FIG. 1 taken along the section line 9-9 in the direction indicated.

FIGURE 10 is a fragmentary sectional view of the apparatus shown in FIG. 9 taken along the section line 1tlll(i in the direction indicated.

Referring principally to FIGURE 1 there is shown my novel tensioru'ng device 1 which includes a tensioning lever or handle 5, a housing 6 which comprises two similar molded members 6a and 6b (FIG. 2) held together by bolts such as bolt 12 (FIG. 2) and whose rear projections serve as a grip for the entire device. There are three rollers 9, lb and 11 positioned at one side of the housing member 6a, the lever 5 being usable to revolve the three rollers and move the strap 3. There is also a trigger 7 which cooperates with a strapping guide and cutting subassembly S and with a tape-holding subassembly 13. The trigger 7 controls the clamping of the strap 3 by the subassembly l3 and the cutting of the strapby the subassembly 8 in a manner to be explained hereinafter. The trigger 7 pivots about a pivot in 20. p The free end of the strapping is first drawn under the package 2; then with the trigger 7 squeezed to release the movable clamp member 1317 the strapping is inserted between the fixed plate 14- and the movable clamp member 13b. It is also drawn between the support member 30 and the strapping guide member 812 with a sufficient length thereof projecting forward of the tool to permit attachment of the seal 4. The trigger '7 is now released allowing the member 13b of self-energizing assembly 13 to press downward on the strapping and clamp it against plate 14. The intermediate portion 3b of the tape has been passed around the package, over the free end 3a and then between the members 8a and 8b. The member 36 is shaped so as to urge the end of the strap upwards so that when the strap is passed around the package and into the guide 8 it will rest upon the end 3a thereby facilitating application of the seal 4 thereto. It is then looped around the roller 9, and 11 as shown and its portion goes to the strapping supply reel (not shown).

One significant feature of this invention is the fact that the intermediate roller 10 is free to move somewhat transversely to its longitudinal axis and is constructed to permit skew for very good reasons as will be explained later. Another significant feature of the invention is that a single pull on the trigger 7 after the seal 4 is put on serves to performthe following functions in sequence. First, the ratchet pawl 7d is released, allowing the rollers 9, 10 and 11 to roll back thus releasing the tension on the strapping through the cut off assembly 8. This is necessary to prevent fraying of the strap when the cutter operates. Secondly, the clamp assembly 13 is released and finally the rotating cutter 8c severs the strap.

Tensioning and strap feed assembly FIGURE 2 shows that the tensioning lever 5 has a gripping end Sa and FIGURE 4 shows that the lever 5 is connected by means of bolts 5!) to a rotating clutch member 9e which is fitted within a bushing 9 set in an opening in housing member 6b. It also has inwardly projecting portions 5c which fit into holes 6c in the member 92. In addition it has an inner recessed portion 5d which fits over the outer end of shaft member 9c.

When the lever 5 is stroked in clockwise and counterclockwise movements it will be seen that the rotating clutch member 9e is similarly moved. Member 96 has an axial bore through which the shaft 90 passes, the shaft 9c having a retaining ring or washer 9p around its external end. Next to the member 9e is a gear member 9d which is adapted to be driven by the member 9e through the intermediary of a spring clutch 29. The clutch is so arranged that it grips the outer surface of the shaft portion of member 9d sufficiently to transmit the rotary motion of member 9e when the lever 5 is stroked in a counter-clockwise direction (as seen in FIG. 1). In the opposite direction the spring is unwound, no force is transmitted to the member 90?, and hence the member 9d does not rotate. The pin 7d mounted on the trigger member 7 operating under pressure supplied by the spring 26 serves as a ratchet pawl allowing the gear 9d to rotate, counter-clockwise, but preventing it from rotating clockwise during the back stroke of lever 5.

The shaft 9c is connected to an enlarged shaft portion 912 that rides in a bushing 9g set within an aperture in the housing member 6a. A dowel pin 9h is disposed in adjacent aligned apertures 9k and 91 located in the gear 9d and shaft portion 9b respectively. The dowel 9h serves to interlock the rotary movement of the two adjacent members 9b and 9d. The shaft portion 9a is integral with the portion 9b and is situated outside of the housing member 6a as shown. It will be noted that the length of the portion 9a is somewhat greater than the length of the corresponding portion 10a of the adjacent roller which, in turn, is somewhat larger than the adjacent roller 11a. These differences are to facilitate the threading of the strap 3 between them in the manner shown in FIG. 1.

The roller assembly 11 includes a shaft portion 11b that is journalled in a bushing lle located in an aperture in the housing portion 6b. There is mounted on the shaft 11b a gear 11d by means of a set screw or pin 11 A bushand arranged to rotate about respective fixed axes there is an intermediate third roller assembly 10 which is so constructed that while it is driven by the gear of the assembly 9 and drives, in turn, the universal roller assembly 11, the external roller portion 10a thereof can move off axis and floa This feature is very important for plastic type strapping with which the device is particularly well-adapted since it enables pressure to be exerted on the strap in the spaces between the roller portions Mia and 11a to be substantially equal to the pressure between the rollers 9a and 10a. This floating action provides a self-energizing effect to tighten the clamping action between the rollers as the strap tension increases. Also, it prevents in those spaces unequal pinching of the strap in its transverse direction, that is in the direction of the width of the tape.

This floating feature is brought about by the particular construction of the roller assembly 19. Gear 10d has a hollow integral shaft which is journaled in a bushing located within an aperture in the housing 6a. The bore of the gear member lltld is somewhat larger than the shaft to permit the aforesaid floating action. The external roller portion 1% includes an axial bore ltle into which one end of the shaft 10b extends. This bore is also some- What larger than the shaft 10b. The roller 113a includes two aligned apertures 10f and 10g which are also aligned with a transverse aperture 1011 located in the shaft 10b. A pin 10k passes through all of the aforesaid aligned apertures. The ends of the pin 10k are tightly fitted into the apertures 10 and 16g but the aperture 10h in the shaft 1% is somewhat larger than the pin. The other end of the shaft 10b is attached to the gear member 10d in identical fashion by means of another pin ltlm disposed at right angles to pin 10k in two aligned apertures (not shown) formed in the gear ltld. The pin 10m also passes through a third aligned aperture 10p in shaft 10b which is larger than the pin. This construction permits the roller 10a to float transversely while being positively driven rotationally by gear 10d.

Clamping and cutting sub-assembly After the tensioning lever 5 has been moved forward and backward a number of times until the strap 3 is subjected to the proper tension, a seal or clip 4 is fastened about the overlapping strap portions as shown in FIG. 1 and then an appropriate crimping tool (not shown) is used to deform the seal 4 and its contents so as to prevent longitudinal motion of the strap thereafter. A tool which has proved highly satisfactory for this purpose produces one or more transverse corrugations in the seal and its contents which extend across the strap from edge to edge. At this juncture, it is desired to cut the strap before it is unthreaded from the rollers 9, 10 and 11.

In accordance with my invention, I have devised a cutting sub-assembly which takes into account, in particular, the characteristics peculiar to fibrous plastic strapping such as the polypropylene strap Amcostrap previously referred to. It is characteristic of highly oriented or fibrous polypropylene strapping to shred when, under high tension, it is cut in a direction transverse to its length. My invention takes into account this characteristic by providing that the tension on the strap is reduced by first al owing the tensioning rollers to reverse and by unclamping the strap from the tool 1 just before the cutting action begins. This is done by coordinating the ratchet release unclamping and cutting actions with a single pull or inward stroke of the trigger assembly.

The trigger 7 is pivoted about a pivot pin 20 which is journalled in appropriate apertures formed in the interior walls of the housing members 6a and 6b. In its rest position as seen in FIG. 3, a spring 26 located within aperture 27 exerts pressure downward about the pin 70 protruding from the trigger so that the latter ordinarily is in its outermost position, that is, in a position furthest from the lower surface of the rear extension of the housing 6. Its movement in both directions is limited by the length of the slot 6 formed in the housing members 6a and 6b. At the lower end of the trigger 7 there is an upward slanting projecting portion 711 on which there is a pin 7d (FIGS. 3 and 5). The pin 7d is constructed to act as an anti-backup ratchet for the gear 9d when the trigger is in its rest position and the lever 5 is being cranked up and down. It will be noted that ordinarily the pin 7d will be pressed between the teeth of the gear 9d because of the downward pressure exerted by the spring 26 upon the trigger 7. However, after the strap has been tensioned and sealed, as soon as the trigger 7 is pulled upward, the pin 7d will be disengaged from the teeth of the gear 9d and the tension on the strap 3 will tend to cause the rollers 9 and 11 to rotate clockwise (FIG. 1) and the roller to rotate counter-clockwise a bit. Consequently the strap 3 will move downward through the rollers and leftward through the guide assembly 8.

Unclamping operation As the trigger 7 is pulled, the back surface of the portion 7a starts to press against the front rounded portion 21b of the lever member 21 causing the latter to pivot about its pivot pin 22. Consequently the portion 21b moves backward while the portion 21a. which is symmetrical thereto moves forward. The lever 21 is positioned so that the portion 21a passes through the space between two inclined plane blocks or members 13a and 13b. The member 13a is bolted or pinned by threaded dowels 18 and 19 (FIG. 6) which are passed through apertures 34 and 35 from below and screwed into aligned threaded apertures in the housing 6a. The member 13b is not fixed at all but is rather movable longitudinally. It is prevented from lateral movement inward by having its internal long side disposed adjacent a parallel flat external surface of the housing portion 6a. Lateral movement outward is prevented by the side-retaining plate 130. Plate 130 is bolted by bolts 13d and 13a which pass through apertures in the plate to threaded apertures 13p and 13g in member 13a. U-s'haped springs and 16 are inserted into apertures 13m and 1311 in members 13a and 13b respectively.

FIG. 7 depicts the strap clamping assembly 13 and 14 in the clamping position (i.e., when the portion 21a has not moved forward) and FIG. 8 depicts the same assembly in the unclamping position. The forward movement of the portion 21a, in response to pressure on the trigger 7, moves the inclined plane clamping member 13b forward and somewhat upward at the same time because the roller 17 is moved between portions of the inclined plane surfaces which are closer to one another than they were in the rest position of the trigger. As a result, there is .a greater clearance between the lower surface of the member 1311 and the upper surface of the stationary member 14 and hence the strap 3 will be released. To provide clearance for movement of the heads of the springs 15 and 16, the plate 13c is provided with triangular hollowed-out sections 13 and 13g on its inner side.

It should be noted that as the trigger 7 is squeezed, a generally C-shaped linkage member 24, one of whose ends 24b is located in an aperture 7b in the trigger is pulled rearward and causes the member 25 to pivot in a counterclockwise '(FIG. 3) direction. The member 25 has its wider end fixed to the shaft portion of cutting member 8a. The shaft portion passes through an apertured inner extension 8a of the guide member 8a (FIG. 9). The inner extension 8a is journalled in an inner projecting portion 60 of the housing part 6a and is held in place by a set screw 28 (FIG. 9). Thus as the member 25 rotates the cutting member 80 also moves counter-clockwise so that the cutting edge 8 of member 8c cuts transversely across the strap against the fixed member 8b. From inspection of :FIGS. 5 and 9 it will be noted that the cutting edge 87'' is canted so that an effective shearing action on the strap is produced starting from the inside edge to the outer edge thereof. This makes the cutting action easier and lessens the pressure required on the trigger.

When the pressure on the trigger is released the decompressive action of spring 26 which coiled around pin 7c causes the trigger to pivot clockwise whereupon the clamping member 1312 is moved back to its rest position (FIG. 7) by the restorative action of springs 15 and 16.

To increase the clamping effect of the movable block 131) its lower surface may be sand-blasted so that when the strap is fed through it will grip the strap better (and thereby increase the clamping action) when the latter is pulled to the right (FIG. 1) yet will not bite into the strap with the attendant risk of tearing it.

Modifications of the novel apparatus disclosed herein which do not depart from the essence thereof will doubtless occur to those skilled in the art on reading this specification. Consequently, I desire my invention to be limited only by the claims which follow.

I claim:

1. In a tool for tensioning a strap disposed about an article and having means for holding one end of said strap, the improvement comprising:

(a) at least three roller means between which an unclamped portion adjacent the other end of said strap is threaded, said strap being curled partially around at least three adjacent ones of said roller means so as to provide a distributed bearing surface for said strap and (b) means for driving said roller means for advancing said strapping so as to increase the tension on said strapping around said article.

2. In a tool as recited in claim 1 wherein there is additionally provided (c) means coupled to said rollers for clamping .and cutting said strapping.

3. In a tool as recited in claim 2 wherein said clamping and cutting means includes means for preventing rotary movement of said roller means in a direction tending to reduce tension on said strapping.

4. The improvement recited in claim 1 in which one of said roller means is constructed and arranged to move transversely to and axially of its axis as well as around said axis thereby enabling the distance between it and adjacent ones of the other rollers tovary so as to tend to increase and equalize the pressure exerted upon said strap by it and said adjacent rollers as the tension on said strapping increases.

5. The improvement according to claim 4 wherein said transversely movable roller means includes an external strapping-contacting portion and a bore therein and also includes a shaft having a portion which enters said bore but has a smaller outer diameter than said bore, wherein said roller means also includes an internal geared member having a bore in which another portion of said shaft passes, the bore of said geared member having a larger diameter than said other shaft portion, wherein said shaft includes first and second apertures formed at opposite ends thereof and whose axes are in quadrature with one another, wherein first and second pins pass respectively through said first and second apertures and have respective diameters smaller than said apertures, and wherein the ends of said pins are respectively disposed in transverse apertures in said strapping-engaging portion and in said geared member, said transverse apertures being respectively aligned with said first and second apertures.

6. The improvement according to claim 4 wherein there are three of said rollers, wherein said movable one of said rollers is positioned between the two other rollers, wherein the roller on which the strapping material first bears after passing around said package has the largest diameter, and wherein said rollers are provided with respective gears coupled thereto, the gear of said first roller being adapted to be driven and to drive the gear of said movable roller which, in turn, drives the gear of said third roller.

7. A tool for tensioning strapping material about an object which comprises:

(a) means for clamping one-end of said strapping prior to commencement of tensioning by said tool,

(b) means for engaging another portion of said strapping and advancing said portion to produce a desired tension on the strapping around said object, and

(c) means coupled to said clamping means for cutting said strapping just after said clamping means is in position to release said strapping.

8. The tool according to claim 7 wherein said clamping means includes means for preventing movement of said advancing means in a direction tending to reduce tension on said strapping and wherein said advancing means. in-

.cludes .a plurality of roller means one of which is constructed to move about its axis and transversely thereto for equalizing and increasing pressure on said strapping as the tension thereupon is increased.

9. Apparatus for tensioning strapping material about an object which comprises:

(a) means for clamping one end portion of said strapping prior to commencement of tensioning by said apparatus, said clamping means including a lower stationary member constructed to be disposed below said strapping, and an upper subassembly, constr-ucted to be disposed above said strapping, said subassembly including a stationary block and a movable block having respective inclined surfaces which face one another and a rolling member between said stationary and moving blocks in contact with said facing surfaces, said subassembly being constructed that when said movable block is moved longitudinally in one direction, the lower surface thereof moves closer to the upper surface of said lower stationary member thereby to grip said strapping ma terial,

(b) a plurality of roller means geared to one another for engaging another portion of said strapping and advancing said strapping in a direction which produces increased tension on said strapping, said plurality of roller means having respectively different lengths to facilitate the threading of said strapping around and between them,

(c) means for revolving at least one of said roller means thereby causing rotation of the other ones thereof,

(d) means through which said strapping is passed for cutting said strapping, and

.(e) actuating means coupled to said cutting means and to said movable block for moving the latter in the 8 direction tending to reduce the clamping action therevof just prior to the initiation of the operation of said cutting means on said strapping.

10. In apparatus for tensioning a strap about an article, means for clamping one end portion of said strap comprising:

(a) a lower stationary member adapted to be positioned below said strap,

(b) an upper subassembly which is adapted .to 'be disposed above said strap, said subassembly including (i) an upper stationary block, ,(ii) a lower movable block, said upper and lower blocks having facing inclined surface portions, (iii) a roller between said blocks and in contact with said inclined surfaces, and (iv) means for moving said lower movable block in a direction which increases the distance be tween its lower surface and the upper surface of said lower stationary member.

11. The invention according to claim 10 wherein the lower surface of said movable block is treated to increase its friction and thereby improve its gripping ability.

12. The invent-ion according to claim 10 with the addition of means for coupling said upper and lower blocks with one another, said coupling means including resilient members which are constructed to bias said movable block in a direction which decreases the distance between .its lower surface and the upper surface of said lower stationary member.

13. The apparatus according to claim 10 wherein said means for moving said movable block includes pivoting means having a portion thereof positioned and arranged for back-and-forth movement betweensaid blocks.

14. The invention according to claim 12 with the addition of a retaining plate coupled tosa'id upper stationary block for limiting the axial outward movement of said roller and the lateral outward movement of said movable block.

155. The invention according to claim 13 with the addition of a trigger for causing said pivoting means to pivot.

References Cited by the Examiner UNITED STATES PATENTS 2,549,626 4/51 Mosey 14Q93.2 3,013,589 12/61 Jones 140-93.2 3,114,399 12/63 Hamilton et al. 140-932 3,129,728 4/64 Sharko 140-93.2

CHARLES W. LANHAM, Primary Examiner. 

1. IN A TOOL FOR TENSIONING A STRAP DISPOSED ABOUT AN ARTICLES AND HAVING MEANS FOR HOLDING ONE END OF SAID STRAP, THE IMPROVEMENT COMPRISING: (A) AT LEAST THREE ROLLER MEANS BETWEEN WHICH AN UNCLAMPED PORTION ADJACENT THE OTHER END OF SAID STRAP IS THREADED, SAID STRAP BEING CURLED PARTIALLY AROUND AT LEAST THREE ADJACENT ONES OF SAID ROLLER MEANS SO AS TO PROVIDE A DISTRIBUTED BEARING SURFACE FOR SAID STRAP AND (B) MEANS FOR DRIVING SAID ROLLER MEANS FOR ADVANCING SAID STRAPPING SO AS TO INCREASE THE TENSION ON SAID STRAPPING AROUND SAID ARTICLE. 